Office Manager

Get to Know Us

Horizon3.ai is a fast-growing, remote cybersecurity company dedicated to the mission of enabling organisations to proactively find and fix and verify exploitable attack vectors before criminals exploit them. Our flagship product, the NodeZeroTM platform, delivers production-safe autonomous pentests and other key assessment operations that scale across the largest internal, external, cloud, and hybrid cloud environments. NodeZero has been adopted by organisations of all sizes, from small educational institutions to government agencies and Global 100 enterprises. It is used by ITOps/SecOps teams, consulting pentesters, and MSSPs and MSPs.

We are a fusion of former U.S. Special Operations cyber operators, startup engineers, and formerly frustrated cybersecurity practitioners. We're committed to helping solve our common security problems: ineffective security tools, false positives resulting in alert fatigue, blind spots, "checkbox” security culture, cybersecurity skills shortage, and the long lead time and expense of hiring outside consultants. Collectively, we are a team of learn it alls, committed to a culture of respect, collaboration, ownership, and results.

As a remote first company, we require minimum 25Mbps consumer grade broadband connection.

We are seeking an experienced and proactive Office Manager to join our team in San Francisco. This role is pivotal in ensuring our office runs smoothly, efficiently, and reflects our culture and values. The ideal candidate is highly organized, resourceful, and thrives in a dynamic, fast-paced environment. You will be responsible for managing daily office operations, supporting leadership and staff, planning and managing events, and creating a welcoming workplace experience. You will be expected to be in the office typically 4-5 days per week. The nature of this role offers visibility from leaders across our growing organization and the chance to showcase ambition to executive leadership, meaning you have the chance to build this role based on your interests and strengths.

What You’ll Do

• Gain hands-on experience across multiple areas — from operations and events to people/culture — giving you a well-rounded foundation for future career growth.

• Bring creativity to life by designing events, initiatives, and office experiences that reflect and strengthen our culture.

• Grow with a company that values curiosity, ownership, and continuous learning — we encourage you to stretch into projects that excite you.

Office Operations & Facilities

• Oversee day-to-day office operations, including supplies, vendors, mail, and facilities management.

• Act as primary liaison with building management, contractors, and service providers.

Events & Engagement

• Plan, coordinate, and manage company events such as networking mixers, holiday parties, all-hands celebrations, and milestone events.

• Organize and execute team offsites and onsite gatherings, ensuring smooth logistics (venues, travel, catering, activities, and budgets).

• Collaborate with leadership and teams to design events that strengthen culture, collaboration, and connection.

• Manage vendor relationships for event services, including caterers, venues, and entertainment.

• Track budgets and ensure events are delivered on time, within scope, and aligned with company values.

People & Culture

• Serve as a key point of contact for employees regarding office-related inquiries.

• Partner with People/HR to promote company culture and employee engagement.

Administrative Support

• Manage our company receptionist service, Ruby - ensuring it’s always online and sending the messages to the correct person internally

• Partner with leadership on scheduling, travel coordination, and special projects.

• Assist with expense reporting, budget tracking, and vendor payments.

What You’ll Bring

• 2+ years of experience in office management, operations, or administrative roles, ideally in a fast-growing company.

• Strong organizational skills with the ability to multitask and prioritize effectively.

• Excellent written and verbal communication skills.

• Tech-savvy with proficiency in tools like Google Workspace, Slack, Zoom, and expense/reporting systems.

• Friendly, approachable, and proactive in anticipating needs.

• Passion for creating engaging, inclusi